Cycling has become increasingly popular in recent times as a form of exercise and recreation. Cyclists are commonplace on today's roads and many cities have defined bicycle trails for road bicycles and off-road or mountain bicycles.
Cycling has also become a common family activity. An infant can accompany a parent by being placed in an infant seat above the rear tire of the parent's bicycle. Infant seats, however, are not of sufficient size to accommodate older children who are not yet old enough to ride their own bicycle. This presents a problem for the parent or family who desires to cycle as a family activity.
Bicycle trailers allow these children to accompany the adults while cycling. A bicycle trailer attaches to the bicycle and is generally of sufficient size to allow two small children to be placed therein. Groceries and other items may be carried in the bicycle trailer either with a child or alone. Thus, bicycle trailers provide many advantages to the cyclist who is a parent and to any cyclist who desires to transport items by bicycle.
U.S. Pat. No. 5,020,814 to George et al. discloses a collapsible bicycle trailer having a tongue or tow bar 75 which is pivotally attached to the chassis frame of the trailer for pivoting between a folded position beneath and adjacent the chassis frame and an extended position in front of the chassis frame (ref. col. 5, lines 25-30). The tow bar is locked in the extended position by a U-shaped clip and a pin.
Notably, to avoid injury to the children, it is important for a trailer which is convertible between a bicycle trailer and a stroller that the device be very stable, particularly in the stroller position where the bicycle is not present and the device is by pushed as a stroller, as opposed to being pulled by a bicycle.
A number of prior art devices for trailers exist. Of these, one of the most relevant is U.S. Pat. No. 5,308,096 to Smith which discloses a bicycle trailer which has a pivotable towing bar which is pivotable from a forwarding and horizontally extending towing position to an upwardly and rearwardly extending stroller position to convert the trailer to a stroller. Front wheel or wheels 52 pivot downwardly into a ground engaging condition when towing bar 28 is pivoted into the stroller position (see FIG. 5 and Col. 4, lines 50-55). Problematically, however, this design disclosed in U.S. Pat. 5,308,096 in the stroller position is essentially only supported at three points, first point being at the point of contact of the front wheel or wheels 52 at the forward end of the vehicle centrally of the vehicle, the second and third points of contact with the ground being respectively at the spaced apart two rear wheels 22. As such, the convertible trailer in the stroller position is inherently less stable than if it were supported at four spaced-apart, independent locations. Such patent does not disclose any manner of retracting a spaced-apart second pair of wheels, located on mutually opposite sides of the chassis frame of the bicycle trailer, and clearly does not disclose or teach any manner of retracting a spaced-apart pair of wheels where the towing bar is pivotably coupled to the frame chasis of the bicycle trailer proximate to and/or preferably at the axis or axle about which the rear (larger) pair of wheels rotate. Towing bars of prior art devices such as Smith, which are pivotably coupled to the trailer more forwardly of the trailer than the rear wheels typically (when rotated upwardly and rearwardly approximately 135.degree. from a substantially forwardly facing horizontal position to an inclined, rearwardly facing position as a stroller handle) are of insufficient length to allow proper use as a stroller handle. Conversely, prior art towing bars if simply made longer result in the trailer being towed by the bicycle at a larger distance, making manoevering of the bicycle-trailer combination more difficult.
Clearly lacking in the prior an is a compact bicycle trailer design which provides for two pairs of wheels, the second pair being spaced apart and being extendible when in the stroller position to provide a stable stroller device having a towing bar of serviceable length, and when in the trailer position having a pivotable towing bar of a compact length to provide a manoeverable bicycle-trailer combination.